Method of making bondable leads using positive photoresist and structures made therefrom

ABSTRACT

A microelectronic component having a plurality of leads are formed at their tip end with bondable material using a process including a mask of positive photoresist material. The leads can be rendered peelable from the substrate by, for example, plasma undercutting the leads. The tip ends of the leads can be bonded to contacts on an opposing microelectronic component, and separated therefrom in horizontal direction by virtue of the peelable leads to form S-shaped leads. The space between the microelectronic components can be filled with a compliant layer to form a microelectronic package.

CROSS-REFERENCED RELATED APPLICATION

[0001] The present patent application claims priority to U.S.Provisional Application No. 60/288,771, filed May 4, 2001, which isincorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

[0002] The present invention relates in general to microelectronicelements and methods of making same, and more particularly, tointerconnection structures having bondable leads made using positivephotoresist material.

[0003] Microelectronic elements such as semiconductor chips areconnected to external circuitry, such as the circuitry of a supportingsubstrate or circuit panel, through electrical contacts on the frontface of the chip. Various processes for making these interconnectionsuse prefabricated arrays of leads or discrete wires. For example, intape automated bonding processes, a dielectric supporting tape such as athin film of polyimide, includes an array of metallic leads on onesurface of the dielectric film. The metallic leads are aligned with thecontacts on the front face of the chip. The dielectric film isjuxtaposed with the chip so that the leads extend over the front orcontact bearing surface on the chip. The leads are then bonded to thecontacts of the chip, such as by ultrasonic or thermocompressionbonding. The terminals on the dielectric film may then be connected toexternal circuitry for electrically interconnecting the chip and theexternal circuitry.

[0004] In various microelectronic packages, it is often desirable toprovide a connection between two components, which can accommodaterelative movement between the components. For example, where asemiconductor chip is mounted to a circuit board, thermal expansion andcontraction of the chip and circuit board can cause the contacts on thechip to move relative to the corresponding electrically conductivefeatures of the circuit board. This can occur during service and canalso occur during manufacturing operations as, for example, duringsoldering operations on the circuit board.

[0005] As illustrated in U.S. Pat. No. 5,518,964 (“the '964 patent”),the disclosure of which is incorporated herein by reference, movableinterconnections between elements such as a semiconductor chip andanother element can be provided by first connecting leads between theelements and then moving the elements away from one another through apreselected displacement so as to bend the leads. For example, aconnection component may incorporate a dielectric body and leadsextending along a bottom surface of the dielectric body. The leads mayhave first or fixed ends permanently attached to the dielectric elementand connected to electrically conductive features such as terminals,traces or the like on the dielectric body. The leads may also havesecond ends releasably attached to the dielectric body. The dielectricbody, with the leads thereon, may be juxtaposed with the chip and thesecond ends of the leads may be bonded to contacts on the chip.

[0006] Following bonding, the dielectric body and chip are moved awayfrom one another, thereby bending the leads towards a verticallyextensive disposition. During or after movement, a curable material suchas a liquid composition is introduced between the elements. This iscured to form a compliant dielectric layer such as an elastomer or gelsurrounding the leads. The resulting packaged semiconductor chip hasterminals on the dielectric body connection component which areelectrically connected to the contacts on the chip but which can moverelative to the chip to compensate for thermal effects. The packagedchip may be mounted to a circuit board by solder-bonding the terminalsto conductive features on the circuit board. Relative movement betweenthe circuit board and the chip due to thermal effects is taken up in themoveable interconnection provided by the leads and the compliant layer.

[0007] In order to achieve bonding of the leads to the contacts on thechip, a bondable material such as tin or tin alloys is deposited ontothe second ends or tips of the leads. The bondable material can bedeposited by electroplating processes using a patterned masked materialand plating solder through the formed openings in the mask. However,electroplating processes are not compatible in certain microelectroniccomponents where the leads are not all electrically interconnected to acommon bus. This is often the case in the aforementioned microelectroniccomponents.

[0008] It is also known to deposit bondable material onto the tips ofleads using conventional solder and reflow application techniques. Thetips of the leads are provided with a metal pad which acts as adiffusion barrier so that the lead material, typically copper, does notdiffuse into the bondable material, as well as to promote wetting of thebondable material during the reflow process. In forming the leads andpads, there is required the multiple application of a photoresist maskwhich is patterned to allow for the sequential deposition of the metallayers forming the leads and pads. Due to the projection of the pads,there is a limitation as to the application equipment which can be usedfor depositing the photoresist material. For example, the projectingpads will interfere with certain roller coating equipment known forapplying photoresist material.

[0009] Accordingly, there is the need for improvements in methods ofmaking microelectronic components having bondable leads by applicationof solder material to the lead tips. There is further the need forimprovements in methods of making microelectronic components whichprovide greater flexibility in photoresist application. Still further,there is the need for methods of making microelectronic components whichuse a single photoresist mask for forming leads and solder ball pads.

SUMMARY OF THE INVENTION

[0010] In accordance with one embodiment of the present invention thereis disclosed a method of making a solder ball pad on a lead supported ona dielectric substrate, the method comprising depositing a positivephotoresist material over a metal layer supported on the substrate;forming an opening in the photoresist material exposing a portion of themetal layer; depositing at least one metal through the opening onto theexposed surface of the metal layer forming a solder ball pad; andremoving the photoresist material from the metal layer.

[0011] The aforesaid method includes enlarging the opening in thephotoresist material and depositing through the enlarged opening a layerof another metal surrounding the solder ball pad, wherein the anothermetal comprises gold and gold alloys, and includes removing portions ofthe metal layer using the photoresist material as a mask to define alead extending from the solder ball pad over the surface of thesubstrate. The method includes depositing a bondable material onto anexposed surface of the another metal, wherein the bondable materialcomprises solder material. The method includes depositing through theopening in the photoresist material a layer of bondable material ontothe solder ball pad, and includes enlarging the opening in thephotoresist material and depositing through the enlarged opening a layerof another metal surrounding the layer of bondable material, wherein thebondable material comprises solder material and wherein the anothermetal comprises gold and gold alloys. The method includes removingportions of the metal layer using the photoresist material as a mask todefine a lead extending from the solder ball pad over the surface of thesubstrate and includes at least partially separating the lead from thesurface of the substrate.

[0012] In accordance with another embodiment of the present inventionthere is described a method of making a microelectronic componentcomprising providing a dielectric substrate having a surface supportingan electrically conductive layer; coating the electrically conductivelayer with positive photoresist material; forming a plurality ofopenings in the photoresist material exposing the electricallyconductive layer therein; depositing a first metal layer within theopenings over the exposed electrically conductive layer; selectivelyremoving the electrically conductive layer to form leads extending overthe surface of the substrate in electrical contact with the first metallayer; and removing the photoresist material from the electricallyconductive layer.

[0013] The aforesaid method includes enlarging the openings in thephotoresist material and depositing through the enlarged opening asecond metal layer over the first metal layer, includes depositing abondable material onto an exposed surface of the second metal layer, andincludes patterning the photoresist material to define the leads priorto the selectively removing the electrically conductive layer, whereinthe thickness of the first and second metal layer is less than thethickness of the photoresist material. The method includes at leastpartially separating the leads from the surface of the substrate andincludes depositing a bondable material through the openings in thephotoresist material over the exposed surface of the first metal layer.The method includes enlarging the openings in the photoresist materialand depositing through the enlarged openings a second metal layer overthe bondable material, wherein the first metal layer comprises nickel,the second metal layer comprises gold and gold alloys and the bondablematerial comprises tin and tin alloys, and includes heating themicroelectronic component to a temperature to cause the bondablematerial to reflow.

[0014] In accordance with another embodiment of the present inventionthere is described a method of making a microelectronic componentcomprising providing a dielectric substrate having a surface supportinga metal layer; depositing a positive photoresist material over the metallayer; patterning the photoresist material to delineate on the metallayer a plurality of pad regions exposed through openings formed in thephotoresist material and a plurality of lead regions covered by thephotoresist material extending over the surface of the substrate fromthe pad regions; depositing a first electrically conductive materialonto the metal layer through the openings in the photoresist material inthe pad regions; removing portions of the metal layer uncovered by thepatterning of the photoresist material to form leads in electricalcontact with the electrically conductive material in the pad regions;and removing residual photoresist material from the metal layer.

[0015] The aforesaid method includes enlarging the openings in thephotoresist material and depositing a second electrically conductivematerial through the enlarged openings onto an exposed surface of thefirst electrically conductive material, and includes depositing abondable material onto an exposed surface of the second electricallyconductive material, wherein the thickness of the first and secondelectrically conductive materials is less than the thickness of thephotoresist material.

[0016] The method includes depositing a bondable material through theopenings onto an exposed surface of the first electrically conductivematerial, and includes enlarging the openings in the photoresistmaterial and depositing through the enlarged openings a secondelectrically conductive material over the bondable material, and furtherincludes heating the microelectronic component to a temperature to causethe bondable material to reflow. The method includes at least partiallyseparating the leads from the surface of the substrate.

[0017] The invention also discloses a solder pad on a lead supported ona dielectric substrate made in accordance with the aforesaid method anda microelectronic component made in accordance with the aforesaidmethod.

[0018] In accordance with another embodiment of the present inventionthere is described a method of making a microelectronic packagingcomprising providing a first microelectronic component having a frontsurface supporting a plurality of contacts; providing a secondmicroelectronic component having a surface supporting a plurality ofleads, the second microelectronic component made by providing adielectric substrate having a surface supporting an electricallyconductive layer; coating the electrically conductive layer with apositive photoresist material; forming a plurality of openings in thephotoresist material exposing the electrically conductive layer therein;depositing a first metal layer within the openings over the exposedelectrically conductive layer; selectively removing the electricallyconductive layer to form leads extending over the surface of thesubstrate in electrical contact with the first metal layer; and removingthe photoresist material from the electrically conductive layer; atleast partially separating the leads from the substrate; positioning thesecond microelectronic component overlying the first microelectroniccomponent; bonding an end of the leads to the contacts with a bondablematerial therebetween; and separating the first and secondmicroelectronic components from each other into spaced apartrelationship whereby the end of the leads remain bonded to the contactsand the other end of the leads remain supported by the dielectricsubstrate.

[0019] The aforesaid method includes enlarging the openings in thephotoresist material and depositing through the enlarged openings asecond metal layer over the first metal layer, and depositing a bondablematerial onto an exposed surface of the second metal layer, wherein thethickness of the first and second metal layers is less than thethickness of the photoresist material. The method includes patterningthe photoresist material to define the leads prior to the selectivelyremoving the electrically conductive layer and at least partiallyseparating the leads from the surface of the substrate. The methodincludes depositing a bondable material through the openings in thephotoresist material over the exposed surface of the first metal layerand enlarging the openings in the photoresist material and depositingthrough the enlarged openings a second metal layer over the bondablematerial, wherein the first metal layer comprises nickel, the secondmetal layer comprises gold and gold alloys and the bondable materialcomprises tin and tin alloys. The method further includes heating themicroelectronic component to a temperature to cause the bondablematerial to reflow.

[0020] In accordance with another embodiment of the present inventionthere is described a method of making a microelectronic packagingcomprising providing a first microelectronic component having a frontsurface supporting a plurality of contacts; providing a secondmicroelectronic component having a surface supporting a plurality ofleads, the second microelectronic component made by providing adielectric substrate having a surface supporting a metal layer;depositing a positive photoresist material over the metal layer;patterning the photoresist material to delineate on the metal layer aplurality of pad regions exposed through openings formed in thephotoresist material and a plurality of lead regions covered by thephotoresist material extending over the surface of the substrate fromthe pad regions; depositing a first electrically conductive materialonto the metal layer through the openings in the photoresist material inthe pad regions; removing portions of the metal layer uncovered by thepatterning of the photoresist material to form the leads in electricalcontact with the electrically conductive material in the pad regions;removing residual photoresist material from the metal layer; at leastpartially separating the leads from the substrate; positioning thesecond microelectronic component overlying the first microelectroniccomponent; bonding the leads to the contacts with a bondable materialtherebetween; and separating the first and second microelectroniccomponents from each other into spaced apart relationship whereby aportion of the leads remain bonded to the contacts and another portionof the leads remain supported by the dielectric substrate.

[0021] The aforesaid method includes enlarging the openings in thephotoresist material and depositing a second electrically conductivematerial through the enlarged openings onto an exposed surface of thefirst electrically conductive material and depositing a bondablematerial onto an exposed surface of the second electrically conductivematerial, wherein the thickness of the first and second electricallyconductive materials is less than the thickness of the photoresistmaterial.

[0022] The method includes depositing a bondable material through theopenings onto an exposed surface of the first electrically conductivematerial and enlarging the openings in the photoresist material anddepositing through the enlarged openings a second electricallyconductive material over the bondable material, including heating themicroelectronic component to a temperature to cause the bondablematerial to reflow.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above description, as well as further objects, features andadvantages of the present invention will be more fully understood withreference to the following detailed description of a method of makingbondable leads using positive photoresist and structures made therefrom,when taken in conjunction with the accompanying drawings, wherein:

[0024] FIGS. 1-8 are sequential front elevational views showing thesteps in a process of making a microelectronic component having leadswith bondable material in accordance with one embodiment of the presentinvention;

[0025] FIGS. 9-14 are sequential front elevational views showing thesteps in a process of making a microelectronic component having leadswith bondable material in accordance with another embodiment of thepresent invention; and

[0026] FIGS. 15-17 are sequential front elevational views showing thesteps in making a microelectronic package using a microelectroniccomponent constructed in accordance with another embodiment of thepresent invention.

DETAILED DESCRIPTION

[0027] In describing the preferred embodiments of the subject matterillustrated and to be described with respect to the drawings, specificterminology will be resorted to for the sake of clarity. However, theinvention is not intended to be limited to the specific terms soselected, and is to be understood that each specific term includes alltechnical equivalence which operate in a similar manner to accomplish asimilar purpose.

[0028] Referring now to the drawings, wherein like reference numeralsrepresent like elements, there is shown in FIG. 1 a substrate 100 formedof dielectric material, for example, polymer material such as polyimideand the like. The substrate 100 may be rigid or flexible having an uppersurface 102. A metal layer 104 is formed on the upper surface 102 of thesubstrate 100. The metal layer may be formed using conventionaltechniques, for example, by electroless or electroplating techniques orlaminating a preformed metal sheet onto the upper surface using asuitable adhesive. The metal layer 104 will ultimately be patterned toform leads, conductive traces, contact pads and/or other conductiveelements of the circuit for the microelectronic component. Hence, themetal layer 104 is preferably formed from copper, copper/gold alloys andthe like.

[0029] A layer of positive photoresist material 106 is applied over theexposed surface of the metal layer 104. The photoresist layer 106 may beapplied using any conventional application technique, such as rollercoating, spin coating, doctor blade and the like. In using positivephotoresist material, the layer 106 is exposed to UV light in a patternwherever the photoresist material is to be removed. Exposure to the UVlight changes the chemical structure of the photoresist material so thatit becomes more soluble in a developer. The exposed photoresist materialis then washed away by the developer solution, leaving windows exposingthe underlying material. Therefore, the photomask (not shown) used inpatterning the photoresist layer 106 contains apertures disposed in apattern corresponding to the pattern which is to be formed on thephotoresist layer. Since only those areas of the photoresist layer 106which are exposed to UV light are removed, a single photoresist layermay be patterned multiple times in a processing sequence to define otherwindows and circuit elements and features as desired. Positivephotoresists other than those which are UV activated can be used such asX-ray or E-beam activated positive photoresists.

[0030] By way of one example, positive photoresist materials include abase resin, a photosensitive compound and an organic solvent.Phenol-formaldehyde polymer is one of the basic resins used in knownpositive photoresist materials. When the polymer is exposed to lightenergy of the desired wavelength, the polymer changes from an insolublestate to a soluble state. This process is referred to asphotosolubilization. The polymer chemistry changes from thephenol-formaldehyde structure to a carboxylic acid, which dissolves inthe base developer. Positive photoresist materials are available from anumber of sources, for example, Kodak and Shipley.

[0031] Using a suitable mask, the positive photoresist layer 106 ispatterned by exposing to light those regions which will form the tips ofthe leads, and hence, the location of application for the bondingmaterial. As shown in FIG. 2, a plurality of openings 108 are formed inthe positive photoresist layer 106 after developing so as to expose thesurface 110 of the underlying metal layer 104. A metal diffusion barrierlayer 112 is deposited through the openings 108 onto the surface 110 ofthe metal layer 104. In accordance with the preferred embodiment, thebarrier layer 112 is an electrolytically plated layer of nickel having athickness of about 5 microns as shown in FIG. 3. The barrier layer 112may be formed from other such metals. The barrier layer forms aplurality of bumps or pads 114 on the surface of the metal layer 104 atthe tip ends of the leads which are to be defined from the metal layerat a later stage in the process of making microelectronic components inaccordance with the present invention.

[0032] Referring to FIG. 4, the positive photoresist layer 106 isexposed a second time to enlarge the openings 108 surrounding the pads114. This second exposure of the positive photoresist layer 106 wouldnot be possible using negative resist material. In this regard, the useof negative resist material would require that the first photoresistlayer be stripped after defining the openings 108 and a second layer ofnegative photoresist be applied in order to form enlarged openings 116.The enlarged openings 116, which surround the pads 114, allow for thedepositing of a metal layer 118 encapsulating the pads 114. The metallayer 118 is preferably a gold layer which is etch resistant,electrically conductive, and wettable to the bonding material to beapplied hereinafter. In accordance with one embodiment, the thickness ofthe barrier layer 112 and metal layer 118 is less than the thickness ofthe photoresist layer 106.

[0033] The metal layer 104 will be etched at a later stage to form theleads, circuit traces and other circuit features using a suitableetchant. The gold layer 118 protects the pads 114 from being etchedduring etching of the metal layer 104. It is therefore contemplated thatthe gold metal layer 118 may be eliminated provided that an etchant isselected which does not attack the barrier layer 112 which forms thepads 114. For example, suitable etchants which will not attack thenickel barrier layer 112 include ammoniacal etchants, i.e., ammoniumbased etchants. Accordingly, although it is preferred to provide metallayer 118 surrounding the pads 114, the metal layer is not considered anessential feature of the present invention.

[0034] The positive photoresist layer 106 is exposed a third time so asto define the leads, traces and other circuit features as shown in FIG.5 by means of openings 119. Using a suitable etchant, the metal layer104 is etched to the upper surface 102 of the substrate 100 to define aplurality of leads 120 and circuit traces 122 as shown in FIG. 6. Thephotoresist layer 106, as shown in FIG. 7, is removed using a suitablepositive photoresist stripper composition which will not attack themetal layers used in forming the pads 114 and leads 120. A variety oforganic solvents can be used such as acids and/or hydrogen peroxidesolutions. Specific positive photoresist stripping material are wellknown in the art which are available from a number of standardcommercial sources.

[0035] A portion of the leads 120 can be made peelable from thedielectric substrate 100 using a variety of techniques. For example,using a plasma etch process, a portion of the substrate 100 underlyingthe leads 120 can be undercut to minimize adhesion and thereforerendering that portion of the leads peelable. By way of example, onesuch lead undercutting process is disclosed in U.S. patent applicationSer. No. 09/020,750 entitled “Components With Releasable Leads” filed onFeb. 9, 1998, the disclosure of which is incorporated herein byreference. Other methods of forming peelable leads are disclosed in, forexample, U.S. patent application Ser. No. 09/200,100 entitled“Connection Component With Peelable Leads” filed on Nov. 25, 1998, thedisclosure of which is incorporated herein by reference. Still othermethods for forming peelable leads which can be used in practicing thepresent invention are disclosed in U.S. patent application Ser. No.09/549,638 entitled “Components With Releasable Leads”, filed on Apr.14, 2000; and U.S. patent application Ser. No. 09/566,273 entitled“Components With Releasable Leads”, filed on May 5, 2000, thedisclosures of which are incorporated herein by reference.

[0036] The leads 120 can be rendered peelable either before or afterapplying bonding material to the leads. In accordance with the preferredembodiment, bondable material 124 is deposited onto the metal layer 118overlying the pads 114 as shown in the left hand portion of FIG. 8. Byway of example, suitable bonding material includes tin, tin alloys,tin-palladium, silver-bismuth, nickel with gold bumps and the like. Thebondable material 124 is heated to a temperature to allow its reflow soas to form the spherical solder balls 126 as shown in the right handportion of FIG. 8. It is preferred that the leads 120 be renderedpeelable after application of the bondable material 124. In this regard,the presence of any photoresist material such as may be used whendepositing the bondable material 124 can affect the rate of undercuttingof the leads. In addition, as the leads 120 once rendered peelable arerelatively weak, the further processing such as application of thebonding material 124 and handling of the substrate 100 can potentiallyresult in damage to the leads. However, as noted hereinabove, it iscontemplated that the leads 120 can be rendered peelable before or afterapplication of the bonding material 124 and/or rendering the bondingmaterial flowable to form the solder balls 126.

[0037] Referring now to FIGS. 9-14, there will be described anotherembodiment of the present invention for making bondable leads usingpositive photoresist material. As shown in FIG. 9, a layer of bondablematerial 124 is deposited through openings 108 in the photoresist layer106 onto the surface of pads 114 formed by the diffusion barrier layer112. The openings 118 are plasma etched to create enlarged openingsaround the bondable material 124 and barrier layer 112 which forms thepads 114. A metal layer 118, for example, such as gold or a gold alloy,is plated through the enlarged opening to encapsulate the bondablematerial 124 and underlying barrier layer 112 as shown in FIG. 10. Byway of example, the metal layer 118 has a portion extending above thesurface of the photoresist material 106. As previously described, thephotoresist material 106 is used as a mask to pattern the metal layer104 to define leads 120 and circuit traces 124 as shown in FIG. 11 viaopenings 119. Upon etching the metal layer 104, as shown in FIG. 12, theleads 120 and circuit traces 124 are defined on the substrate 100. Thephotoresist material 106 is stripped using a suitable stripper material,as previously described, thereby exposing the surface of the leads 120and traces 122 as shown in FIG. 13. Subsequently, the bondable material124 is heated to reflow the material thereby forming solder balls 126 asshown in FIG. 14. During the reflow process, the metal layer 118,preferably gold, will diffuse into the bondable material 124. Theunderlying barrier layer 112 will prevent the copper layer fromdiffusing into the bondable material 124 during the reflow process, aswell promoting wetting. In the manner as previously described, the leads120 can be rendered peelable from the dielectric substrate 100.

[0038] The completed microelectronic component 128, 130 can be used in avariety of interconnection applications such as interposers and the likefor forming microelectronic packages with another microelectroniccomponent such as a semiconductor chip. With reference to FIGS. 15-17, amicroelectronic component 134, such as a semiconductor chip,semiconductor wafer, circuitized printed circuit board and the like hasa plurality of contacts 136. A microelectronic component 128, 130 ispositioned opposing the contact face side of the microelectroniccomponent 134. As specifically shown in FIGS. 15 and 16, the solderballs 126 on each of the leads 120 are aligned with a correspondingcontact 136 on the microelectronic component 134. The leads 120 on themicroelectronic component 128, 130 are bonded to the contact pads 136via the solder balls 126 as shown in FIG. 16.

[0039] The microelectronic components are vertically, and preferablyalso horizontally separated from one another by using any suitablemeans. For example, the microelectronic components 128, 130, 134 may berespectively attached to an upper or lower platen (not shown) such as byvacuum. The vertical and horizontal movement of the platens will causethe leads 120 to peel from the surface of the substrate 100 to bevertically extended and form a generally S-shaped configuration as shownin FIG. 17. During or after the separation of the microelectroniccomponents, a flowable material such as a liquid composition 138 capableof curing to form a compliant dielectric material such as a gel or anelastomer can be injected between the microelectronic components. Forexample, the curable liquid composition 138 may be a silicone or epoxycomposition which forms a compliant flexible body. On the other hand, itis also contemplated that a curable liquid composition 138 may be in thenature of a rigid polymer material if desired. If the liquid composition138 is injected during the movement step, the pressure of thecomposition will help to force the microelectronic components, such as asemiconductor chip or wafer, a packaged chip or a multichip module awayfrom each other either with or without assistance from the platens. Theliquid composition 138 is then cured to form a compliant dielectriclayer.

[0040] The leads 120 may be terminated around the periphery of thesubstrate 100 by the conductive traces 122 extending outwardly to thesubstrate periphery whereby there can be provided contact pads (notshown). In addition, the substrate 100 may be formed with one or moreconductive vias 132. The vias may be formed as plated through holesthrough the substrate 100 to electrically contact one end of the leads120. The other end of the vias may be provided with contacts 140 on theopposing surface of the substrate 100. The vias 132 in addition to beingthrough holes, may also be filled with a metal material, such as abondable material for connection to another microelectronic component.

[0041] Although the invention herein has been described with referenceto particular embodiments, it is to be understood that these embodimentsare merely illustrative of the principles and application of the presentinvention. It is therefore to be understood that numerous modificationsmay be made to the illustrative embodiments and that other arrangementsmay be devised without departing from the spirit and scope of thepresent invention as defined by the appended claims.

1. A method of making a solder ball pad on a lead supported on adielectric substrate, said method comprising: depositing a positivephotoresist material over a metal layer supported on said substrate;forming an opening in said photoresist material exposing a portion ofsaid metal layer; depositing at least one metal through said openingonto the exposed surface of said metal layer forming a solder ball pad;and removing said photoresist material from said metal layer.
 2. Themethod of claim 1, wherein said at least one metal comprises nickel. 3.The method of claim 1, further including enlarging said opening in saidphotoresist material and depositing through the enlarged opening a layerof another metal surrounding said solder ball pad.
 4. The method ofclaim 3, wherein said another metal comprises gold and gold alloys. 5.The method of claim 3, further including removing portions of said metallayer using said photoresist material as a mask to define a leadextending from said solder ball pad over the surface of said substrate.6. The method of claim 5, wherein at least a portion of said lead ispeelable from said substrate.
 7. The method of claim 3, furtherincluding depositing a bondable material onto an exposed surface of saidanother metal.
 8. The method of claim 7, wherein said bondable materialcomprises solder material.
 9. The method of claim 1, further includingdepositing through said opening in said photoresist material a layer ofbondable material onto said solder ball pad.
 10. The method of claim 9,further including enlarging said opening in said photoresist materialand depositing through said enlarged opening a layer of another metalsurrounding said layer of bondable material.
 11. The method of claim 10,wherein said bondable material comprises solder material.
 12. The methodof claim 10, wherein said another metal comprises gold and gold alloys.13. The method of claim 10, further including removing portions of saidmetal layer using said photoresist material as a mask to define a leadextending from said solder ball pad over the surface of said substrate.14. The method of claim 13, further including at least partiallyseparating said lead from the surface of said substrate.
 15. The methodof claim 10, further including heating said bondable material and layerof another metal to reflow said material and said metal to form a solderball therefrom.
 16. A method of making a microelectronic componentcomprising: providing a dielectric substrate having a surface supportingan electrically conductive layer; coating said electrically conductivelayer with positive photoresist material; forming a plurality ofopenings in said photoresist material exposing said electricallyconductive layer therein; depositing a first metal layer within saidopenings over the exposed electrically conductive layer; selectivelyremoving said electrically conductive layer to form leads extending oversaid surface of said substrate in electrical contact with said firstmetal layer; and removing said photoresist material from saidelectrically conductive layer.
 17. The method of claim 16, furtherincluding enlarging said openings in said photoresist material anddepositing through said enlarged opening a second metal layer over saidfirst metal layer.
 18. The method of claim 17, further includingdepositing a bondable material onto an exposed surface of said secondmetal layer.
 19. The method of claim 17, further including patterningthe said photoresist material to define said leads prior to saidselectively removing said electrically conductive layer.
 20. The methodof claim 19, wherein the thickness of said first and second metal layeris less than the thickness of said photoresist material.
 21. The methodof claim 16, further including at least partially separating said leadsfrom said surface of said substrate.
 22. The method of claim 16, furtherincluding depositing a bondable material through said openings in saidphotoresist material over the exposed surface of said first metal layer.23. The method of claim 22, further including enlarging said openings insaid photoresist material and depositing through the enlarged openings asecond metal layer over said bondable material.
 24. The method of claim23, wherein said first metal layer comprises nickel, said second metallayer comprises gold and gold alloys, and said bondable materialcomprises tin and tin alloys.
 25. The method of claim 23, furtherincluding at least partially separating said leads from said surface ofsaid substrate.
 26. The method claim 23, further including heating saidmicroelectronic component to a temperature to cause said bondablematerial to reflow.
 27. A method of making a microelectronic componentcomprising: providing a dielectric substrate having a surface supportinga metal layer; depositing a positive photoresist material over saidmetal layer; patterning said photoresist material to delineate on saidmetal layer a plurality of pad regions exposed through openings formedin said photoresist material and a plurality of lead regions covered bysaid photoresist material extending over said surface of said substratefrom said pad regions; depositing a first electrically conductivematerial onto said metal layer through said openings in said photoresistmaterial in said pad regions; removing portions of said metal layeruncovered by said patterning of said photoresist material to form leadsin electrical contact with said electrically conductive material in saidpad regions; and removing residual photoresist material from said metallayer.
 28. The method of claim 27, further including enlarging saidopenings in said photoresist material and depositing a secondelectrically conductive material through said enlarged openings onto anexposed surface of said first electrically conductive material.
 29. Themethod of claim 28, further including depositing a bondable materialonto an exposed surface of said second electrically conductive material.30. The method of claim 28, wherein the thickness of said first andsecond electrically conductive materials is less than the thickness ofsaid photoresist material.
 31. The method of claim 27, further includingat least partially separating said leads from said surface of saidsubstrate.
 32. The method of claim 27, further including depositing abondable material through said openings onto an exposed surface of saidfirst electrically conductive material.
 33. The method of claim 32,further including enlarging said openings in said photoresist materialand depositing through said enlarged openings a second electricallyconductive material over said bondable material.
 34. The method claim33, further including heating said microelectronic component to atemperature to cause said bondable material to reflow.
 35. The method ofclaim 33, further including at least partially separating said leadsfrom said surface of said substrate.
 36. The method claim 27, whereinsaid patterning of said photoresist material to delineate said padregions occurs prior to patterning of said photoresist material todelineate said lead regions.
 37. A solder pad on a lead supported on adielectric substrate made in accordance with the method of claim
 1. 38.A microelectronic component made in accordance with the method of claim16.
 39. A microelectronic component made in accordance with the methodof claim
 27. 40. A method of making a microelectronic packagingcomprising: providing a first microelectronic component having a frontsurface supporting a plurality of contacts; providing a secondmicroelectronic component having a surface supporting a plurality ofleads, said second microelectronic component made by providing adielectric substrate having a surface supporting an electricallyconductive layer; coating said electrically conductive layer with apositive photoresist material; forming a plurality of openings in saidphotoresist material exposing said electrically conductive layertherein; depositing a first metal layer within said openings over saidexposed electrically conductive layer; selectively removing saidelectrically conductive layer to form leads extending over said surfaceof said substrate in electrical contact with said first metal layer; andremoving said photoresist material from said electrically conductivelayer; at least partially separating said leads from said substrate;positioning said second microelectronic component overlying said firstmicroelectronic component; bonding an end of said leads to said contactswith a bondable material therebetween; and separating said first andsecond microelectronic components from each other into spaced apartrelationship whereby the end of said leads remain bonded to saidcontacts and the other end of said leads remain supported by saiddielectric substrate.
 41. The method of claim 40, further includingenlarging said openings in said photoresist material and depositingthrough said enlarged openings a second metal over said first metallayer.
 42. The method of claim 41, further including depositing abondable material onto an exposed surface of said second metal layer.43. The method of claim 41, wherein the thickness of said first andsecond metal layers is less than the thickness of said photoresistmaterial.
 44. The method of claim 40, further including patterning saidphotoresist material to define said leads prior to said selectivelyremoving said electrically conductive layer.
 45. The method claim 44,further including at least partially separating said leads from thesurface of said substrate.
 46. The method claim 40, further includingdepositing a bondable material through said openings in said photoresistmaterial over the exposed surface of said first metal layer.
 47. Themethod of claim 46, further including enlarging said openings in saidphotoresist material and depositing through the enlarged openings asecond metal layer over said bondable material.
 48. The method of claim47, wherein said first metal layer comprises nickel, said second metallayer comprises gold and gold alloys and said bondable materialcomprises tin and tin alloys.
 49. The method of claim 47, furtherincluding heating said microelectronic component to a temperature tocause said bondable material to reflow.
 50. The method of claim 47,further including at least partially separating said leads from saidsurface of said substrate.
 51. A method of making a microelectronicpackaging comprising: providing a first microelectronic component havinga front surface supporting a plurality of contacts; providing a secondmicroelectronic component having a surface supporting a plurality ofleads, said second microelectronic component made by providing adielectric substrate having a surface supporting a metal layer;depositing a positive photoresist material over said metal layer;patterning said photoresist material to delineate on said metal layer aplurality of pad regions exposed through openings formed in saidphotoresist material and a plurality of lead regions covered by saidphotoresist material extending over said surface of said substrate fromsaid pad regions; depositing a first electrically conductive materialonto said metal layer through said openings in said photoresist materialin said pad regions; removing portions of said metal layer uncovered bysaid patterning of said photoresist material to form said leads inelectrical contact with said electrically conductive material in saidpad regions; removing residual photoresist material from said metallayer; at least partially separating said leads from said substrate;positioning said second microelectronic component overlying said firstmicroelectronic component; bonding said leads to said contacts with abondable material therebetween; and separating said first and secondmicroelectronic components from each other into spaced apartrelationship whereby a portion of said leads remain bonded to saidcontacts and another portion of said leads remain supported by saiddielectric substrate.
 52. The method of claim 51, further includingenlarging said openings in said photoresist material and depositing asecond electrically conductive material through said enlarged openingsonto an exposed surface of said first electrically conductive material.53. The method of claim 52, further including depositing a bondablematerial onto an exposed surface of said second electrically conductivematerial.
 54. The method of claim 52, wherein the thickness of saidfirst and second electrically conductive materials is less than thethickness of said photoresist material.
 55. The method of claim 51,further including depositing a bondable material through said openingsonto an exposed surface of said first electrically conductive material.56. The method of claim 55, further including enlarging said openings insaid photoresist material and depositing through said enlarged openingsa second electrically conductive material over said bondable material.57. The method of claim 56, further including heating saidmicroelectronic component to a temperature to cause said bondablematerial to reflow.
 58. The method claim 56, further including at leastpartially separating said leads from said surface of said substrate byremoving portions of said substrate underlying said leads.
 59. Themethod of claim 51, further including at least partially separating saidleads from said surface of said substrate by removing portions of saidsubstrate underlying said leads.
 60. The method of claim 51, whereinsaid patterning of said photoresist material to delineate said padregions occurs prior to patterning of said photoresist material todelineate said lead regions.
 61. A microelectronic package made by themethod of claim
 40. 62. A microelectronic package made by the method ofclaim 51.